Electric soldering iron for small work



Oct. 23, 1956 R. A. KUHN ET AL ELECTRIC SOLDERING IRON FOR SMALL. WORK Filed May 16, 1955 INVENTORS ROBER'T A. KU H'N BY CHARLES A.HANSER zm'mm MW ATTORNEYS United States Patent Ofiice ELECTRIC SOLDERING IRON FOR SMALL WORK Robert A. Kuhn, Grosse Pointe, and Charles A. Hanser, Detroit, Mich., assignors to American Electrical Heater Company, Detroit, Mich., a corporation of Michigan Application May 16, 1955, Serial No. 508,518

Claims. (Cl. 219-26) The invention relates to electrically heated soldering irons and it is the object of the invention to obtain a construction particularly adapted for use in connection with small work.

It is a further object to obtain a construction in which the heated unit may be easily detached and replaced at any time.

With these and other advantageous features in view the invention consists in the construction as hereinafter set forth.

In the accompanying drawings:

Fig. 1 is a perspective view of our improved soldering lron.

Fig. 2 is an enlarged longitudinal section through the tool partly in elevation.

Fig. 3 is a cross section on line 3-3, Fig. 2.

As the device is only intended for use with small work the tool unit A is of minimum dimensions. Thus, the tool proper A has a tapering wedge shaped point A and a tubular shank A integral therewith. Within the tubular shank is a heating unit which includes a tubular core member B of ceramic material and a resistor C wound thereabout. This unit is surrounded by comminuted insulating material, such as magnesia, which is packed within the tubular shank A The resistor extends beyond the rear end of the shank and is packed within an insulator tube D. The core member B extends rearward still further, having one of the terminals of the resistor connected to a contact E surrounding said core. The terminal connection to the opposite end of the resistor passes through the hollow core and has a contact member E at its inner end. Said contacts E and E are connected to the energizing circuit as will be later explained.

The handle F is hollow and preferably formed of insulating material. G is a metallic tube having a portion thereof within the hollow handle F anchored thereto, preferably by a threaded engagement with an annular nut member H. The tube G projects out from the handle and forms a socket for receiving the tool unit A.

It is necessary that the tool unit A should be secured within its socket with suflicient rigidity to withstand the stresses to which it is subjected in the performance of its work but it is also desirable to limit thermal conduction between the members A and G. This we accomplish by placing within a portion of the tube G a radially resilient bushing I, preferably formed of a thin wall resilient 2,768,275 Fatented Oct. 23, 1956 tube having longitudinally extending corrugations I' therein. This is not only resilient but also it limits the surface contact between the corrugated tube and each of the members A and G. By forming the corrugated tube of material which is low in thermal conductivity and is also relatively noncorrodible, such as stainless steel, the double purpose is accomplished of limiting thermal conduction and preventing adhesion. We also preferably provide a series of apertures G in the tube G which connect the spaces within the corrugations with the external atmosphere.

In connecting the unit to the handle the conductor cord I is first threaded through the hollow handle and tube G and has its separate conductors connected to the contacts E and E by sleeves J, P. The shank A may then be inserted within the tube G to engage the resilient bushing I, whereupon the tool is ready for use. At any time the unit A may be easily replaced by another similar unit, this being facilitated by the non-corrosive character of the surface of the bushing and also its radial resiliency.

What we claim as our invention is:

1. An electric soldering tool comprising a hollow handle, a tube of smaller diameter having a portion within and anchored to said handle and a portion projecting therefrom, a tool member having a soldering point and integral hollow shank, a ceramic tubular core, a resistor wound on said core with a forward terminal end portion thereof passing rearward through the tube, comminuted refractory insulating material packing said resistor and a portion of said core within said hollow shank, and with a portion of the core and terminal portions of the resistor projecting rearward therefrom for connection of the latter with electric service condctors, and a radially resilient thin wall corrugated bushing within the projecting portion of said tube for receiving said shank and securing said tool member to the handle.

2. The construction as in claim 1 in which said corrugated tube is formed of corrosion resisting material.

3. The construction as in claim 1 in which said corrugated tube is formed of stainless steel which is relatively low in thermal conductivity.

4. The construction as in claim 1 in which said tube is apertured for the passage of cooling air into said corrugated bushing.

5. The construction as in claim 1 in which the current supply conductor may be threaded through said hollow handle and tube and connected to said tool mem her in advance of engagement of the latter with said bushing.

References Cited in the file of this patent UNITED STATES PATENTS 1,572,666 Marsden Feb. 9, 1926 2,180,665 Bruggerman Nov. 21, 1939 2,422,265 Squires June 17, 1947 2,721,251 Thomas Oct. 18, 1955 FOREIGN PATENTS 424,072 Italy Aug. 5, 1947 

